I made a bunch of these in a single, frantic day of
silkscreening, and would love to give them to similarly-minded
folks.

My cost was about $6 per shirt (American Apparel, made in Los
Angeles by non-sweatshop labor) plus materials. I'll happily
send you one for a sawbuck. I will warn you, however, that the
shirts vary: the silkscreening on some is smudged, crooked,
uneven, and patchy, because I didn't really know what I was
doing. (Maybe the next batch will be better.) Shirts are orange
design on random colors, in a mix of sizes. Email me and let
me know what size you want and I can tell you what I have.

I'm working on another design that will be much cooler. Keep in
touch.

Don't get the joke? I don't blame you. Here's the explanation
I wrote up to go with the shirt:

Around the first century BCE, a few hundred years after the
death of the Buddha, there arose new schools of Buddhist
thought. In contrast to the previous emphasis on personal
enlightenment, these schools emphasized compassion, venerating
the bodhisattva — a being who, although enlightened and able to
enter Nirvana, remains in the world to help all other beings
attain freedom from suffering. This new movement called itself
the Mahayana, the "Great Vehicle", implying that it was large
enough to carry everyone to enlightenment. They referred to the
older schools derisively as Hinayana, the "Lesser Vehicle," a
name which didn't win them any friends. The Mahayana is still
represented today in China, Japan, Vietnam, and elsewhere, and
includes Zen.

I admit it, it's a bad pun. But when someone asks you what your
shirt says, the short answer is, "the great vehicle which
carries everyone to enlightenment."